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J. H. BIOKFORD.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM. No. 349,976. Patented Sept. 28, 1886.

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JOHN H. BIOKFORD, OF SALEM, MASSACHUSETTS, ASSIGNOR OF ONE-THIRD TO S. FRED SMITH, OF SAME PLACE.

AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 349,976, dated September 28, 1886,

Application filed January 18, 1886. Serial No. 188,965.

To all whom it may concern.-

Be it known that 1, JOHN H. BIOKFORD, of Salem, county of Essex, and State of Massachusetts, have invented an Improvement in 5 Automatic TelephoneExchange Systems, of

which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

[ This invention is an improvement upon application for Letters Patent filed by me November 25, 1885, Serial No. 183,970.

The invention has for its object to provide the subscribers station with a call or signal I box of improved construction, together with means for restoring the same to its normal condition after being used; also, to provide the central office with a selecting-instrument similar to that descr.bed in the said application,

for governing the electrical connection between difi'erent lines, but containing a disk of suitable construction, that as the pen wipes over the same the line will not be broken; also, to provide more efficient means for operating the said selectinginstrument. The call or signal box at the subscribers station consists of a break-wheel, a suitable motor for rotating the same, a pointer mounted upon the break-wheel shaft, and a series of stops which,

0 when depressed, check the rotation of the pointer, thereby determining the number of breaks or total interruptions transmitted over the line. The stops to limit the rotation of the break-wheel are herein shown as arranged 3 5 in a circle and spring-controlled, and suitable locking devices are supplied whereby the said stops are locked in their depressed condition while conversation is being carried on over the line, and automatic devices, controlled by 40 the weight of the telephone, release the said locking devices and permit the box to resume its normal condition. The selectinginstrument at the central office, consisting of a frame having disks secured thereto, a ro- 4 5 tating shaft carrying suitable pens which wipe over the peripheries of the disks, and a ratchetwheel and pawl for rotating the said shaft, is similar to that shown in the application referred to, and the disks to which the subscribers lines are interchangeably connected are provided upon their peripheries with a series of conducting-stops, and upon their sides with asimilar series of conducting-stops ar- No model.)

| ranged alternately with relation to the first series, the series located upon the side of the disk being insulated from the other series and having a common ground terminal. The arm attached to the rotating shalt carries two pens, one of which wipes over the periphery of the disk while the other wipes over the conduct- 6o ing-stops located upon the side of the said disk, which, as previously stated, are arranged alternately with relation to the peripheral series, so that as the shaft is rotated one pen passes from stop to stop upon the periphery of the disk, and the other pen makes contact with its stop just as the first pen leaves its stop, so that a continuous groundterminal is given to the line until the desired connection has been made. The pawl for engaging the ratchet-wheel to rotate the shaft carrying the disks is controlled by the springcontrolled armature of an electro-magnet in local circuit, said local circuit being controlled by the armature of a polarized magnet located 7 5 in the main line.

Figure 1 shows in side elevation a call or signal box constructed in accordance with this invention, also showing automatic means for restoring the apparatus to its normal position; Fig. 2, a detail to be referred to; Fig. 3,

a diagram of one of the selectirig-instruments located at the central office-and means for controlling its operation; Fig. 4., a face View of one of the disks.

The call or signal box to be herein described is located at the subscribers station, as in the application referred to, and the result to be obtained by it is similar to that described in the said application. The box consists of a baseplate, A, having suitable frame -work mounted thereon to support and give bearing to the various parts. The break wheel a, mounted upon the shaft (4, has its bearings in the base-plate A, said shaft being rotated by 1 a motor consisting of a train of wheel-work, B, or other suitable motor. A pointer, b, is mounted upon the break-wheel shaft a, and is restrained from rotation at a normal point by a pivoted finger, I). As the break-wheel is rotated, the finger sweeps over the surface of the plate 0, forming a portion of the framework. A series of stops, d, are located above the plate a, sliding in suitable sleeves, (1, depending from the top plate, (1", and, as herein [05 shown, are arranged in a circle, there belng six such stops contained in the box herein shown. The stops are held in elevated position by spiral springs 01, interposed between the top plate, d, and the capd of the said stops. -When the stops are depressed, their beveled end portions, 2, pass over wires 3, extending across holes 4, of any suitable shape, cut in the plate 5, located beneath the plate 0, said plate 5 having an elongated opening, 7, surrounded by insulating material, (see Fig. 2,) through which thebr'eak-wheel shaft passes, that the plate 5 may move backward and forward against the tension of the spring 8 as the beveled portion of the stop d strikes the said wire 3, the lower ends of the stops being notched to form a catch to thereby lock them in their depressed condition. The pen f, cooperating with the break-wheel, is connected with a batter B which latter is preferably located at the central ofiice and grounded, and

the break-wheel shaft is connected to the main line 10,which is connected with the selecting- .instrument at the central office.

When it is desired to send a call, the finger b is turned on its pivot, releasing the pointer, and one of the stops d is depressed. The pointer is then moved by its shaft until it strikes the shank portion of thedepressed stop, and the break-wheel a, consequently moving simultaneously with the shaft, is stopped when the pointer stops, and there being as many breaks upon the break-wheel as there are stops it will be seen that the operator, by depressing a certain stop, can determine the number of times the line shall be broken. The stop is retained in depressed condition, the pointer bearing against it during the time that conversation is being carried on, the plate 5 having a ground-terminal, as at G, so that the line at such time is grounded. During the time that the stop 01 is depressed and conversation is carried on the telephone T is disengaged from the hook t of the magneto-bell M, such movement permitting the pawl m, connected with the lever m, which, in turn, is connected by link m to the hook t, to engage the next toot-h of the ratchet m mounted upon the shaft m, said ratchet being restrained from backward rotation by the spring-controlled pawl m pivoted to the block m. The shaft m, having its bearing in the side of the bell-box M, carries a break-wheel, m which is engaged at intervals by the pen in, said pen normally resting in a break. The pen m is connected by branch 15, leading from the battery-wire 10. The electro-magnet m is interposed in the branch circuit thus formed, which, when energized, attracts the pivoted armature m, the oppositeend of which is connected by the link m to the arm m, attached to or integral with the movable plate 5 of the call or signal box.

By the attachment herein described, applied to, the side of the magneto-bell, the stop d of the call or signal box is released from its engagement with the plate 5, as follows: The telephone T is hung upon the hook it, the weight of said telephone moving the lever m against the tension of the spring 14, and rotating the ratchet-wheel m and consequently the breaket-wheel m pawl m and by wire 16 to the ground G After the stop d has been released the pointer will travel over the dial until it strikes the stop b. The main line 10 from the subscribers station enters the central office, and is connected with the selecting'instrument S, located therein, which latter is of substantially the same construction as shown and described in the application referred tonamely, consisting of the frame-work n 77., supporting the disks a it and having pivots a n upon which the shaft it turns, said shaft n carrying the arms 12 n", which carry the pens a n making contact with the conductingstops located upon the periphery of said disks n 11. The shaft it also carries the ratchet-wheel 0, having an engaging-pawl, 0, by which the shaft is rotated and the pens made to move about the disks. In this instance I have shown the pawl o as connected to the spring-controlled armature 0 pivoted at 0 of the electro-magnets 0, in local circuit with the local battery B said local circuit being controlled by the vibrating armature 0 of a polarized magnet, P, interposed in the main line, the movement of the said armature 0 being controlled by the interruptions in the line, in this instance caused by the break-wheel of the call-box, so that if the break-wheel rotates sufficiently to transmit three pulsations, the local circuit of the battery B will be closed, thereby moving the ratchet-wheel 0, with its shaft a, three teeth. Normally the current passes over the line 10, polarized magnet P, shaft n arm n, pen a, and by wire 20 to the ground G and as the shaft is rotated and the pen n caused to travel from stop to stop'upon the disk of, to prevent the linebeing broken asecond series of stops,

p, is located upon the side or face of the disk tact the pen it makes its contact, and the se- -ries 19, being grounded at G a continuous ground-terminal is given to the line until the proper connection has been made.

By the employment of a polarized magnet herein described currents of one polarity may be passedtherethrough to control the local circuit, while reverse currents coming from another subscriber and passingtherethrough will not operate the said local circuit, and very strong currents may be employed, and by employing local circuits, such as herein described, to operate the selecting-instruments,

which may, as in the application referred to, be of any suitable number, the large amount of battery-power at the central office, and extending over the line is materially reduced.

I claim- 1. In a telephoneexchange system, the combination, substantially as described, with a'call or signal box containing a break-wheel, cooperating pen, and motor for revolving said break-wheel, a movable finger, b, and pointer I), normally in contact therewith and connected in circuit with the main line, aseries of independently-movable arresting-stops for arresting the movment of the break-wheel at any predetermined point, of a selecting-instrument, substantially as described, governing the electrical connection with various subscribers, and means, substantially as described, controlled by the interruptions of the break-wheel in the call or signal box for controlling the operation of said selecting-instrument.

2. In atelephone-exchangesystem, the combination, substantially as described, with a call or signal box containing a break-wheel, cooperating pen, and motor for revolving said break-wheel. a movable finger, b, and pointer b, normally in contact therewith and connected in circuit with the main line, a series of independently-movable arrestingstops for arresting the movement ofthebreak-wheel at any predetermined point, and a locking device,substantially as described, having a ground-terminal, for locking the arresting-stops intheir lowermost position, of a selectinginstrument, substantially as described, governing the electrical connection with various subscribers lines, and means, substantially as described, controlled by the interruptions of the break wheel in the call or signal box for controlling the operation of said selecting-instrument.

3. In atelephone-exchange system, the combination, substantially as described, with a call or signal box containing a break-wheel, cooperating pen, and motor for revolving said break-wheel, a series of independently-movable arresting-stops for arresting the movement of the break-wheel at any predetermined point, and a locking device, substantially as described, for locking the arrestingstops in their lowermost position, and means, substantially as described, operated by a weight, for automatically releasing said locking device, thereby restoring the call or signal box to its normal position, of a selecting-instrument, substantially as described, governing the electrical connection with various subscribers lines, and means, substantially as described, controlled by the interruptions of the brealv wheel in the call or signal box, for controlling the operation of said selectinginstrument.

4. In an electric circuit, the combination, substantially as described, of a call or signal box containing a break-wheel, cooperating pen,and motor,and a series of independentlymovable arresting-stops to arrest the movement of the break-wheel at a predetermined point, a locking device, substantially as described, for locking said arresting-stops in their lowermost position, and releasing mechanism consisting of a branch circuit, electromagnet therein, and a breakwheel automatically operated by a weight, also in said branch circuit, to control the electro-magnet.

5. In an electric circuit, the combination, substantially as described, of a call or signal box containing a break-wheel, cooperating pen,and motor,and a series of independentlymovable arresting-stops to arrest the movement of the break-wheel at a predetermined point, and a movable plate, 5 having holes corresponding in number with the number of arresting-stops, through and beneath which the said arresting-stops pass and catch, an electro-magnet in a branch circuit for mov-' ing said plate 5, a break-wl'ieel and co-operating pen also in said branch circuit, a ratchetwheel upon the break-wheel shaft and co operatingpawl therefor, and the springcontrolled lever automatically moved by a weight, whereby the break-wheel is rotated to change the condition of the branch circuit and operate the electro-magnet.

6. In an electric circuit, the combination, substantially as described, of a selecting-instrument consisting of a disk having conducting-stops to which various subscribers lines are interchangeably connected, an intermittingly-moving pen co-operating with said conducting-stops, a rotating shaft to which said pen is attached, and a second series of conducting-stops located upon said disk alternately positioned with relation to the first series of conductingstops and insulated therefrom, an intermittingly-moving pen co-operating with said second series of conduct ing-stops, and means, substantially as described, controlled from a distance for rotating said shaft to move the pens simultaneously.

7. In an electric circuit, the combination, substantially as described, of a selecting-instrument consisting of a disk having conducting-stops to which various subscribers lines are interchangeably connected, an inter mittingly-moving pen cooperating with said conducting-stops, a rotating shaft to which said pen is attached, and a second series of conducting-stops located upon said disk alternately positioned with relation to the first series of conducting-stops and insulated therefrom, an intermittingly -moving pen co-operating with said second series of conductingstops, a ratchet -wheel mounted upon said shaft, a pawl connected with the armature of an electro-magnet for intermittingly rotating said shaft, a polarized magnet controlled from a distance, and a branch circuit controlled by said polarized magnet, in'which the electro-magnet controlling the movement of the ratchet-wheel is interposed.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN H. BICKFORD.

\Vitnesses:

B. J. NoYns, 1 CUTTER. 

